The present invention relates to steering wheels which comprise an annular rim connected by a plurality of radial arms to a hub for fixing to a steering shaft.
It is well known that automobile vehicle steering wheels must be light and easy to use and moreover have a low polar inertia and great strength so as not to break under the action of vibrations due to the motion of the vehicle or under the effect of a shock or the like. For this purpose, they are usually formed by a metal frame preferably composed of wire or tube which is covered with a polyurethane foam or the like affording an attractive appearance and comfort for the driver.
In order to render them lighter, it has been proposed, as described in the U.S. Pat. No. 4,448,091, to form the rim by means of a tube curved into the shape of a ring and bent at its ends so as to constitute a radial arm for fixing to the hub. Unfortunately, such a steering wheel has only one radial arm, which does not afford the comfort required by the vehicle drivers, and moreover the steering wheel is often insufficiently strong.
It has also been proposed, as described in the United Kingdom patent 1,571,902, to form the rim by means of a hollow tube and to connect it by solid arms to a hub moulded onto the ends of these arms. The steering wheel may in this way have the desired number of radial arms, but its weight and size are increased.